Answer:
a prezygotic barrier
Explanation:
Both wild tigers and lions are said to be reproductively isolated.
Reproductive isolation is defined as the existence of barrier between organisms of different species such that they cannot reproduce.
The mechanisms of reproductive isolation varies. While some act to prevent the formation of zygotes (in case of mating) between organisms of different species, some ensures that the resulting zygotes are invalid.
Reproductive isolation mechanisms that act to prevent fertilization and formation of zygotes are referred to as prezygotic mechanisms while those that ensure that invalid zygotes result (in case of successful fertilization) are referred to post zygotic mechanisms.
<em>The natural differences in the ranges of wild tigers and lions ensure that both animals do not mate with each other, let alone results in zygote. This is a form of pre-zygotic reproductive isolation mechanism.</em>
The answer is b because the global warming only gets caused by the decrease of in consumer spending .
Creationists criticize the idea of natural selection as a circular argument, or tautology, claiming "the fittest are those that survive, and survival is how fitness is defined. "
The definition of natural selection is not tautological because natural selection is measured by contribution to the next generation, not simply survival of an individual organism.
Tautologies or circular arguments are true at all times and therefore are not productive as theories since they cannot be disproved. A tautology is a statement which is true by necessity.
Natural selection is the prevalent theory which explains biological change by predicting the mechanism behind evolution.
Nevertheless, natural selection can be explained non-tautologically. It should be described as the theory which tries to speculate as well as retrodict evolutionary change by environmental forces affecting the organisms.
To learn more about natural selection here
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Answer:
Demography is the statistical study of human populations. Demography examines the size, structure, and movements of populations over space and time. It uses methods from history, economics, anthropology, sociology, and other fields.
It radiates light and heat, or solar energy, which makes it possible for life to exist on Earth. Plants need sunlight to grow. Animals, including humans, need plants for food and the oxygen they produce. Without heat from the sun, Earth would freeze.
